The present invention relates to a method of and to an apparatus for assembling rod-shaped articles of the tobacco processing industry. More particularly, the invention relates to a method and apparatus for assembling tobacco-containing rod-shaped articles and filter rod sections into groups which are ready for conversion into filter cigarettes, cigars or cigarillos of unit length or multiple unit length. For the sake of simplicity, the tobacco-containing articles will be referred to as plain cigarettes and the filter rod sections will be referred to as filter plugs of double unit length. However, it is to be understood that the novel method and apparatus can be resorted to with equal advantage for the assembly of groups which can be converted into filter tipped smokers' products other than filter cigarettes.
The making of limited or short series of filter cigarettes is often desirable and necessary for use in laboratories, e.g., to test different brands of tobacco. The customary high-speed filter tipping machines are not ideally suited for such purposes because their output is very high and their use for purposes other than mass production of commercially salable filter cigarettes is unwarranted in view of the very high losses which result from conversion of such machines for the making of short series of filter cigarettes which are to be tested in laboratories for appearance, quality, smell and/or other characteristics.
Many presently popular high-speed filter tipping machines are designed to advance a succession of plain cigarettes of double unit length sideways (i.e., at right angles to the axes of the cigarettes), to sever successive cigarettes midway between their ends so that each such cigarette yields two plain cigarettes of unit length, to move the thus obtained pairs of plain cigarettes of unit length axially and away from one another so as to provide room for insertion of a filter plug of double unit length, to insert the plugs of double unit length between successive pairs of coaxial plain cigarettes of unit length, to drape uniting bands around the filter plus of double unit length and the adjoining end portions of plain cigarettes of unit length so as to convert each such group of rod shaped articles into a filter cigarette of double unit length, and to convert successive filter cigarettes of double unit length into filter cigarettes of unit length by severing the filter cigarettes of double unit length midway between their ends, i.e., across the convoluted uniting bands and the filter plugs of double unit length.
In accordance with another prior proposal which is disclosed in U.S. Pat. No. 2,649,761, filter cigarettes of double unit length are formed by placing two discrete magazines next to a drum-shaped conveyor storing in each magazine a supply of plain cigarettes of unit length. The two magazines supply plain cigarettes of unit length into spaced-apart portions of successive flutes of the conveyor so that the gaps between the pairs of coaxial plain cigarettes of unit length are sufficiently wide to allow for insertion of filter plugs of double unit length. The machine which is disclosed in this patent is designed for mass production of filter cigarettes. It has been found that such machine is rather expensive, primarily or to a large extent because it must be equipped with pairs of discrete magazines for plain cigarettes of unit length which entails the provision of pairs of devices which deliver plain cigarettes of unit length to such magazines. Moreover, the magazines take up a substantial amount of space, especially if they are to store relatively large quantities of plain cigarettes of unit length so that the machine can remain in operation for a reasonably long interval of time even if the supply of fresh plain cigarettes to the magazines is interrupted. Such machine is not suited for the production of relatively short series of filter cigarettes because its space requirements, cost and weight are excessive.